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Related-Party Disclosures - Schedule of Structured Consolidated Entities (Detail) - Consolidated structured entities [member] | 12 Months Ended
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Dec. 31, 2018
Stantec Architecture Inc. [member] | North Carolina, United States [member] |
Disclosure Of Significant Consolidated Structure Entities [Line items] |
Jurisdiction of Incorporation | North Carolina, United States
Stantec Architecture Ltd. [member] | Canada [member] |
Disclosure Of Significant Consolidated Structure Entities [Line items] |
Jurisdiction of Incorporation | Canada
Stantec Geomatics Ltd. [member] | Alberta, Canada [member] |
Disclosure Of Significant Consolidated Structure Entities [Line items] |
Jurisdiction of Incorporation | Alberta, Canada
Stantec International Inc. [member] | Pennsylvania, United States [member] |
Disclosure Of Significant Consolidated Structure Entities [Line items] |
Jurisdiction of Incorporation | Pennsylvania, United States

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